1. Field of Invention
The present invention pertains generally to a device and method for adjustably attaching fins to a sportboard. The invention is particularly, but not exclusively, useful for attaching fins in a manner that allows for quick and convenient adjustment of the position of a fin on a sportboard to maximize the sportboard performance.
2. Description of Related Art
Sportboards, such as surfboard and sailboards, are well known in the prior art for providing recreational enjoyment. Typically, between one to four fins are attached to the underside of the board for facilitating stability and maneuverability. The fins have often been permanently mounted to the underside of the board.
However, there are several disadvantages to permanently mounting a fin to a board. Specifically, the fin cannot be easily removed and replaced if it becomes damaged. Further, the fin cannot be replaced with another fin having different performance properties. This would be advantageous if the user wishes to experiment with different fin configurations according to prevailing wind and surf conditions. Still further, a permanently mounted fin makes the surfboard unwieldy and difficult to transport. For the above reasons, it would be desirable to have fins that can be detachably mounted to the surfboard.
In addition to being detachable, it would be helpful to be able to adjust the position of a fin relative to the board when it is attached. In particular, to maximize the effectiveness of a fin for a variety of wind and surf conditions, it is important to be able to change the longitudinal position of the fin on the board. It is also desirable to be able to change the fin roll angle, i.e., the angle the fin makes with respect to the underside of the board. Additionally, it is important to be able to adjust the fin by hand or with a small tool which would fit within a swimming suit or a wetsuit pocket without causing any discomfort to the wearer.
U.S. Pat. No. 6,139,383, which issued to Barry A. Jolly et al for an invention entitled xe2x80x9cFin Assemblyxe2x80x9d, discloses a fin attachment system wherein a mounting device having a front socket and a rear socket is embedded within a surfboard. A fin having predetermined projections are respectively inserted into the front socket and rear socket and fixed thereto by set screws. For the device as disclosed by Jolly et al, however, there is no tag slot or pin slot in the socket mounting to permit longitudinal movement or adjustment of the fin roll angle.
U.S. Pat. No. 5,997,376, which issued to Block et al for an invention entitled xe2x80x9cSurfboard Fin Mounting Systemxe2x80x9d, discloses a fin that is adjustably attached to a box which is embedded within the surfboard. (The box is mounted in an opening cut into the surfboard.) The box includes a tag slot, but not a pin slot, and the fin is detachably fixed to the surfboard by passing a fastener through the top of the surfboard and threading the fastener into the fin. For the device disclosed by Block et al, however, the fin and tag lack versatility because they are a single integral unit. Further, the tag interfits within the tag slot in a manner which allows for longitudinal adjustment only. Additionally, it is undesirable to place an unsightly opening in the surfboard for installing a contrasting box which visibly extends through the surfboard.
U.S. Pat. No. 5,672,081, which issued to Whitty for an invention entitled xe2x80x9cSurf Fin Fixing Systemxe2x80x9d, discloses a detachable fin wherein two spaced-apart tabs extend downwardly from the fin. The tabs are inserted into slots within a fixing element which is embedded in the surfboard and fixed thereto by a set screw which is obliquely inserted into the fixing element until it contacts a tab. However, Whitty does not envision any structure for adjusting the fin longitudinal position or fin roll angle. The main emphasis of Whitty is simply to provide a fin removal system.
In the light of the above, it is an object of the present invention to provide a sportboard fin attachment system that allows for quick and easy attachment and removal of the fin from the board. It is another object of the present invention to provide a sportboard fin attachment system that allows for adjustment of both longitudinal fin position and fin roll angle relative to the board. Yet another object of the present invention is to provide a sportboard fin attachment system wherein the user can adjust the longitudinal fin position and fin roll angle by hand or with a small implement which can be comfortably stowed in a swimsuit or wetsuit. Still another object of the present invention is to provide a sportboard fin attachment assembly which is easy to install on a sportboard and has significant durability. Another object of the present invention is to provide a sportboard fin attachment system which is easy to manufacture in a cost efficient manner.
As used herein, the term xe2x80x9csportboardxe2x80x9d is intended to mean all types of boards used in water such as surfboards, wakeboards, sailboards and body boards. The term is also intended to encompass all types of watercraft such as boats, kayaks, canoes and catamarans.
The sportboard fin mounting system of the present invention includes a fin engagement enclosure that is fitted into a sportboard recess. The enclosure has an enclosure attachment means that includes a tag slot that extends into the enclosure and longitudinally along the length of the enclosure. The tag slot merges into an orthogonal pin slot, which similarly extends longitudinally within the enclosure. The tag slot and pin slot combine to define an undercut opening for receiving a fin connector assembly.
Ideally, the fin engagement enclosure is molded as a single integral structure. However, for ease of manufacture and assembly within a sportboard, the enclosure comprises the combination of plug and socket parts. The pin slot is formed in the plug, while the tag slot is formed in the socket. The plug and socket parts are fixed together to establish the above-described overall enclosure structure.
The plug part includes a clamp portion through which extends the elongated pin slot. The pin slot is defined by flexible upper and lower clamp portions. The clamp includes friction engagement means comprising, among other things such as serrations, ribs, dimples and roughened surfaces, a plurality of upper notches in the upper clamp portion and corresponding lower notches in the lower clamp portion.
To fix a fin to a sportboard, the fin is provided with a linkage means that includes a downwardly projecting tag having an outwardly extending tag pin. When the tag is inserted into the tag slot, the tag will be simultaneously inserted into the pin slot. The upper clamp portion is urged towards the lower clamp portion by a drive means to cause one of the upper notches and one of the lower notches to engage the pin and hold the tag within the tag slot.
The drive means may comprise a cam mechanism, stem bolt and nut combination or a grub screw as shown herein. The grub screw is threaded into a grub screw opening in the socket that is proximate the upper clamp portion when the plug is inserted into the socket. As the grub screw is turned, part of the screw passes through the grub screw opening and contacts the upper clamp portion. Further tightening of the grub screw imparts a force onto the upper clamp portion that urges the upper clamp portion towards the lower clamp portion as described above to secure the tag pin.
To adjust the longitudinal position of the fin, the grub screw is loosened until the upper and lower clamp portions move away from and disengage the tag pin. Next, the fin is moved forward or backward into any one of a number of predetermined locations defined by the respective upper and lower notches (Corresponding pin location means such as indicator fingers, may be formed in the socket to enable the user to determine which upper notch and lower notch are engaging the pin). Next, the grub screw is re-tightened as described above to engage the tag pin and fix the fin to the sportboard.
To secure the fin engagement enclosure to the sportboard, a recess is formed in the underside of the sportboard. Next, at least one transverse bore is made that extends from a side edge of the board into the sportboard core until it intersects with the recess. The enclosure is placed, in the recess so that it rests on outriggers, and resin is poured into the recess. The resin files the portion of the recess not occupied by the enclosure, as well as the transverse bore(s). When the resin hardens, the enclosure will be fixed within the board, while the hardened resin within the transverse bore will reinforce the overall assembly. After hardening, excess resin is sanded away until the outer surface of the enclosure is smooth and co-planar with the underside surface of the board.
The assembly of the present invention further includes a tilt means for angling the fin relative to the sportboard underside. This is accomplished by making the aforementioned tag detachable from a fin and the enclosure. The tag is preferably a solid polygonal structure having first and second sidewalls and opposing end walls. It has a top surface with a tag attachment means comprising a longitudinal guide channel that extends into the upper face and along at least a portion of the length of the tag. The top surface of the tag matingly engages a corresponding bottom surface of the fin base underside.
The underside of the fin base is provided with a fin connector structure comprising a longitudinal guide rail having a round cross-sectional shape that corresponds to the diameter of the guide channel. For attachment, the guide rail is inserted into the tag guide channel and is moved until the tag contacts a stop means proximate an end of the guide rail. To achieve a variety of fin roll angles, substitute tags are provided that have top surfaces that are beveled at selected angles. When the beveled top surface is engaged with the fin underside, the fin will become aligned at an angle that is complementary to the tag top surface bevel angle.